1. Field of the Invention
The present invention relates to a distributed data processing system having several local systems (LS), each local system having at least one central processing unit (CPU) with its associated memory, peripherals and processes, where the communication between said LS's takes place via a general communications network and where the control of said data processing system is distributed over the respective local systems.
2. Description of the Prior Art
Technological progress made in the field of large scale integrated circuits (LSI) and their low cost are causing an evolution in the architecture and use of data processing systems towards distributed systems. Also, different kinds of processors are beginning to appear, such as processors (CPU) reserved solely for users, special purpose processors (allocation of resources, data base management, communications, etc.) and service processors.
In addition, the local interconnection of data processing systems distributed over the operating areas of an organization, having as objectives communications and the sharing of resources, imply that procedures and protocols are defined which make possible the initialization of the distributed systems, communication between user application programs and the best possible use of resources by sharing phase among said applications. The Appendix contains a selection of references to the prior state of the art.
All the references given in the Appendix are of a general nature. In reference (1) it seems that the distributed control of the overall system is based in each LS which, in this case, is a processor with its main store. References (2) and (3) describe a distributed communications network for packet data transmission in which the user process and resources are distributed. In this system, however, all the processing units are identical and the interconnections between units are made via a "bus" hierarchy. References (4) to (7) describe either distributed processing (4) or distributed control (5 and 6), or the distribution of all the components of a system (7).